Case Report: Rare Presentations of Accidental Subdural Block in Labor Epidural Anesthesia

Abstract

The incidence of accidental injection or catheterization of the subdural space during performance of a neuroaxial block has recently increased. It can occur even when an experienced practitioner performs the neuraxial procedure. The presentation of numerous unexplainable clinical signs in the process of continuous epidural anesthesia, which do not fit the clinical picture of subarachnoid or intravascular injection, should envoke a high suspicion for unintentional subdural block. We report two cases of patients who achieved prolonged labor analgesia via epidural technique with only half the initial loading dose of local anesthetic. Both patients also had short episodes of hypotension. Additionally, one patient presented with severe hypoxemia and mild motor block of both upper and lower extremities. The other patient presented with transit unresponsiveness without motor block. Both patients rapidly responded to vasopressors. Desaturation in one patient, however, was persistent lasting for more than four hours. Her bedside chest X-ray was inconclusive “possible pulmonary edema” and the follow up Chest CT Scan on the second day revealed aspiration pneumonia. Based on the clinical findings, these two cases were suggestive of subdural block with cranial nerve involvement.